GPS failure.Then what?

[Bill Roosa]

Buck!!

I sail all the time without GPS. We have a Friday night sail and even venture into the darkness with out the aid of GPS to get us home!!! Dang, I must be a stud by your reckoning.
It is a little known fact that if you turn 180 degrees you will return to your start point provided you account for tide, wind, leeway, helm-person error......

I think your comment that "WE" will not go out of site of land with out electronics is pretty dumb. That is the "FUN" part of sailing!!!! Getting a little out of control, not really knowing where you are to 4 decimal points, not getting permission from my GPS to proceed.

I'm with Ross, grab a sextant, a quarts watch, your almanacs, and some paper charts and you can navigate better (we have better charts you know) than our fore-fathers.

The real question is after 4 days of overcast skies, will your dead reckoning position jive with the sextant fix you got during a momentary break in the clouds to shoot Jupiter, Saturn, and the Moon over the course of 3 hours!!! And which will you believe!!

 

[Skipper]

Conclusion

Thanks all for the great analysis'.

It appears nearly unanimous that in order for the average (average) sailor to find position when the GPS quits and visibility is obscured by distance, fog (even with a couple miles view), darkness or a combination thereof, he would have to have known how far he had traveled and in what direction from the last known fix.

While soundings are a splendid concept, it would only be effective in this Pacific region near the mainland coast. As when you travel more than 1\2 mile from shore of most of the Channel Islands you are in at least 300 feet of water which quickly increases to 2,500 only a few miles out. Most sounders aren't much good after 500 feet unless you have some abnormal powerhouse, which most(most) private sailboats don't. And in any case this option would not be exactly accurate for navigation.

The above mentioned depths also exclude anchoring from the options, however in other regions this is an outstanding safety decision.

My conclusion may be annoyingly obvious however it has opened my eyes to a healthy fact: When sailing out of sight of land and\or navigating a foreign port, a sailor must record his position, heading and bearing to his destination at scheduled intervals and not rely solely on the GPS.

I am a seasoned sailor however am guilty (as well as many, average, novice, seasoned) of being as lax in maritime navigation as if driving a car up State. I have sat back for hours with the tiller pilot synced with the GPS and occasionally watched the bearing pointer tittle around at the correct course while reading "Incredible Voyage" and sipping root beer. While the sails were full and the boat ship shape and zipping along, analog navigation was disregarded and left to the amazing electronics which have made me lazy by default.

On rare occasion I would check my ship compass heading and GPS distance traveled and make a mental note just because I had thought of it. However in reality if the scenario discussed here actually occurred I would likely have no idea how far I had traveled (I don’t currently use\reset the log in the sounder\speed\water temp unit. I use the GPS stats), what my exact heading was when it quit (when did it quit?) and how to SAFELY navigate to a fog enclosed island some 50 more miles offshore with a 2 knot perpendicular current and only a general idea of my specific boat’s leeway depending on wind speed.

I would have to turn around and head east to land until I had line of sight and return to port.

I speculate that an average sailor or a novice may actually become hopelessly mixed up and, out of VHF range, find his way to different currents\winds and out to open ocean. Maybe that’s how some of these recent Dana Point sailors have been lost. One guy’s Catalina 30 found it’s way to Hawaii, a dismasted ghost ship.

I will now make a better effort to record stats at intervals and brush up on my DR chart navigation. However celestial navigation is still a mystery beyond the basics.

For Bill Roosa: This was not a question of STARTING a trip under chart navigation or how much fun that is. I think the title was clear enough: “GPS Quits, then what.” Turning 180 and accounting for “tide, wind, leeway, helm-person error” is great if you know what these factors are and can accurately and consistently correct for them…at night…out of sight of land..with some minor fog… and if you knew your position and what your heading was. I can reasonably deduce that many(many) sailors can’t do the above, especially when in foreign waters, which was also a parameter for the discussion, if you actually read it. BTW you forgot current and magnetic compass error.

We all know some people are great and amazing and nothing harms them. As stated previously, I can find my way around my patch as everyone here can, GPS or not. This topic was for the many sailors who may have become lax in navigation and whose safety may be improved, even somewhat, by this discussion. We know who we are and it is logical to assume that we are a significant group, if not the majority. My task was to merely discuss and improve.

Good sailing.

 

[Rick D]

Don't Forget, Skipper...

...I think most Chart Plotters have an automatic log function which, assuming the unit didn't dump, will provide you with fixes. The first time I went to Catalina Island from MDR in maybe 1971, we missed the west end at night despite careful planning. At the last minute, I asked one of my mates to double check the heading. He read it from a course guide rather than the chart and picked the wrong departure port! Anyhow, keeping a running on your location is really a good idea. I don't but it's still a good idea. Rick D.

 

[Bill Roosa6491]

GPS usage

Well there seems (to me) that there are two camps on GPS usage. Those of us who grew up without them and pay attention to things like where we are because we had to and those who have always had GPS and did not develop the habit of ALWAYS knowing where you are because they did not have to.
I don't mean this a a criticism, just an observation. I can say the same thing about my use of the compass. And as soon as GPS is a bullet proof as a compass (that day is coming BTW) I'll trust it with my life.

 

[Ross]

Re: Conclusion

There are some interesting observations that may be made while hand steering with a magnetic compass and watching your true course with a GPS. Consider if there is an ebb current of 1 knot at 90 degrees to your steered course and your boat speed is 5 knots. You will be one mile off course in an hour. your GPS will show your actual course over the bottom and you will have to compensate for the set. If you watch the current flow around buoys and if you set a compass course and pick a land mark you can learn to see the set. I like to just sit in a flat glassy calm and watch the course and speed of the boat as it drifts. I save my reading for after the anchor is down. I take great pleasure in seeing how the boat moves with the water.